Sound recording and sound reproducing and locating apparatus



W 193$. F. M. DOOLHTTLE I EJ 3 9 .SOUND RECORDING AND S OUND REPRdDUCING AND LOCATING APPARATUS Original Fil ed June 14, 1921 Q I 46 2 m 7 1,

' INVENTOR -FP\ANKL\N .DOOLITTLE 40 I BY I g i ATTORNEY Patented Aug. 9, 1938 UNITED STATES PATENT OFFICE SOUND RECORDING AND SOUND REPRO- DUCING AND LOCATING APPARATUS poration of Delaware Original application June 14, 1921, Serial No.

477,360. Patent No. 1,817,177.

Divided and this application July 3, 1931, Serial No.

1 Claim.

The present invention relates to sound recording, reproducing and locating apparatus and is directed in particular to a sound recording system capable of producing a record which when reproduced will evoke in the mind of the listener a sense of the motion which occurred at the point from which the sound originates, this application being a division of application Serial No. 477,360, filed June 14, 1921, now Patent No. 1,817,177.

A principal object of the present invention is to provide a system and method which is capable of translating sounds originating at any selected point into a plurality of recorded impulses, each of which sets of impulses corresponds to time separated records of the same sound as varied in accordance with the time of arrival of the sound from the original source with respect to a pair of fixed predetermined points from which the sound is picked up, may then be reproduced so as to furnish two separate reproduced versions of the same sound. Thus, when a listener hears the sound thus reproduced, it is possible for the listener to picture the movement which occurred at the point from which the original sound was translated into a recording.

Still other and further objects of the invention will become apparent and will suggest themselves to those skilled in the art to which the invention relates, by reading the following specification and claim in connection with the accompanying drawing, wherein:

Fig. 1 is a diagrammatic view of one form which a sound-recording, sound-reproducing and locating apparatus embodying my invention may assume.

Fig. 2 is a broken detail view partly in elevation and partly in section showing one method of recording two separate versions of the same sounds, this device being also applicable, when reversely used, to simultaneously reproduce these two separately-recorded versions of the same sounds.

Fig. 3 is a diagrammatic View showing an apparatus for reproducing two versions of the same sounds.

Fig. 4 is a broken detail view showing the transmitting of two separate versions of the same sounds to the ears of a listener by acoustic means. Fig. 5 is a diagrammatic view showing electrical means for transmitting two separate versions of the same sounds tothe ears of the listener.

To the listener to any phonograph as at present made and used, the sounds reproduced by it appear to emanate from a single point. For illustration, in the phonographic reproduction of a musical performance, the listener receives no impression whatever as to the relative location of the respective musicians and their instruments. ments or both are engaged in the performance reproduced, the music appears to proceed from a single point. The same thing is true in the entire range of the use of the phonograph, which distorts the sounds reproduced by it in so far as it eliminates the question of location. The described peculiarity of sounds reproduced by the phonograph appears to be due to the fact that correct sensations of the location of the emission of sounds depends upon the use of both ears and that this sense of location is measurably impaired, if not destroyed, when one ear only is available. With the end in view of taking advantage of the auditory principle just stated, the object of my invention is to provide a method of and apparatus for recording and reproducing sounds in such a manner that the listener will receive the two-fold impression of the sounds, whatever their character and the direction from which they emanate, as, for instance, the location upon a stage of several musicians and their instruments.

With these ends in view, my invention consists in a method of simultaneously producing two separate versions of the same sounds, which versions may diiier in phase relation, and in thereafter simultaneously reproducing those separate versions, in which the difference in time relation has been permanently recorded, and conveying them to the respective ears of the listener. My invention further consists in a duplex-sound-recording instrument for recording two versions of the same sounds, and two soundreceivers leading from the said instrument and separated from each other by substantially the separation of the human ears.

My improved apparatus may assume a variety of forms according to the use to be made of it, as, for instance, phonograph recording, phonograph reproducing, the transmission of music or speeches from one point to another and the like. My improvement may also be embodied in a detectaphone, enabling not only voices to be heard but their relative location to be visualized. My improvement may also be used as an accessory to moving pictures and synchronized therewith so that the voices will shift positions with the movement of the people in the pictures.

For the illustration of my invention, I have chosen receivers 6 and 1, arranged to operate No matter how many voices or instrutelephone-transmitters or microphones 8 and 9 which are mounted or installed so as to be separated from each other by a distance corresponding to the separation of the ears of the average individual, this particular feature being the main structural characteristic of my invention, insofar as it provides for the permanent recording of two versions differentiated in time relation of the same sounds, which is the basic concept of my invention. The sounds gathered by the receivers 6 and l are amplified by amplifying apparatus I0 and II, and led to telephone receivers I2 and I3 having horns l4 and 15 respectively arranged in line with sound-receivers l6 and I! leading to sound-recorders l8 and I9 furnished with needles or points in direct contact with a sound-recording disk 22 of ordinary character, except insofar as it has two continuous spiral grooves running side by side instead of a single groove. By means of such an apparatus, two separate versions differentiated in time relation of the same sounds are simultaneously but separately recorded.

When a duplex sound-locating record made in the manner just described is reproduced, as for instance by an apparatus like that shown in Fig. 2, the extraordinary illusion is created in the mind of the listener of the relative position of the instruments or vocalists or speakers at the time when the musical performance or speech recorded was going on. The illusion is still further heightened by the additional illusion of the relative movement of any of the musicians, or speakers, during the making of the record, so that the listener in his minds eye sees the musicians or speakers move about upon the stage or in the room where they are,

In Fig. 3 I have shown a phonograph 23 mounting a record 24 which it is to be assumed, contains two spiral grooves produced as already described. These spiral grooves respectively receive the needles of the sound-reproducers 25 and 26 connected with the acoustically-insulated airpassages 2i and 28 of a tone-arm 29 leading to telephone transmitters 30 and 3| connected in the usual manner with telephone receivers 32 and 33 joined by a head-band 34. When the telephone receivers 32 and 33 are applied to the ears, the illusion is created of placing or locating the musicians taking part in the performance recorded.

Of course, it would be possible to connect the two tone-arms 21 and 28 acoustically as shown in Fig. 4, instead of utilizing an electric system of transmission, an illustration of which is shown in Fig. 5, in which the sound-receivers 39 and 40 of telephone transmitters 4| and 42 are respectively connected by conducting wires 43 and 44 to telephone receivers 45 and 46 joined by a headband 47. Whatever the form of apparatus employed for recording and reproducing sounds under my invention, it is essential that the same sounds be recorded by sound receiving means so installed as to receive the sounds in a manner simulating or approximating the reception of sounds by the ears of a person similarly located.

Having thus described my invention, what I claim is:

In a means for recording sounds, a source of sound energy, a plurality of spaced microphones each adapted to receive an independent train of energy of the same sound wave whereby a plurality of variations of the same sound are produced, means associated with each of said microphones for amplifying the sound energy, and means for separately recording the output of each microphone on a permanent record, said record comprising a separate path for each train of sound energy whereby the recorded sound when reproduced evokes in the mind of the listener a mental picture of substantially the relative location from which the various sounds originally came.

FRANKLIN M. DOOLI'ITLE. 

